Provide a PXE-bootable memtest86
memtest86 would be useful for diagnostics, prompted specifically by our recent die-off of pc3000 nodes with parity errors. There are a number of recipes out there for
pxelinux based booting (e.g., http://www.panticz.de/node/198), so this would be easiest in a world with a pxelinux-based Emulab boot (#243), but it should be doable even with our
pxeboot, the booting would most likely have to be built in (i.e., a menu option). There is also the issue of how to then non-interactively configure the run of memtest86.